Continuous motion container molding machine

ABSTRACT

A CONTINUOUS MOTION CONTAINER MOLDING MACHINE IS PROVIDED WITH COOPERATING MOLDS WHICH OPERATE UPON HEATED THERMOPLASTIC SHEET OR WEB MATERIAL TO FORM DISPOSABLE CONTAINERS. THE HEATED SHEET MATERIAL WEB IS CONTINUOUSLY DELIVERED TO THE COOPERATING MOLDS, THE TRANSFER THEREBETWEEN BEING ACCOMPLISHED BY CIRCUMFERENTIAL WEB CLAMPING MEANS ALONG A COINCIDENTAL PATH WHEN SYNCHRONIZED WITH THE SPEED OF THE MOVING WEB,   THEREBY ENABLING THE COOPERATING MOLD MEANS TO FORM THIN-WALL, SUBSTANTIALLY UNIFORM-IN-THICKNESS, CONTAINERS FROM THE MATERIAL CLAMPED OFF FROM THE REMAINDER OF THE MOVING WEB. UNIQUE SUBSTATIONS OF THE CONTINUOUS MOTION CONTAINER MOLDING MACHINE INCLUDING SHEET DELIVERY, WEB CLAMPING, SCRAP REMOVAL, AND CUP EJECTION SUBSTATIONS ARE ALSO DISCLOSED.

B. EDWARDS Sept. 20, 1971 CONTINUOUS MOTION CONTAINER MOLDING MACHINEFiled July 28, 1969 11 Sheets-Sheet l INVIiN'l'UR.

dwards 24 41 @0 His Aff'ys Bryan! BY Sept. 20, 1971 B. EDWARDS comluuousuonou coumusa MOLDING momma Fi1ed.Ju1y 2a, 1969 ll Sheets-Sheet 8INVI5NI'HR. Bryanf Edwards B. EDWARDS 3,605,192

CONTINUOUS MOTION CONTAINER MOLDING MACHINE Sept. 20, 1971 11Sheets-Sheet 5 Filed July 28, 1969 lNVIiN'l'UR. Bryanf' Edwards BY fl/ZlHis art' s Sept. 20, 1971 EDWARDS 3,605,192

CONTINUOUS MOTION CONTAINER MOLDING MACHINE Filed July '28, 1969 11Sheets-Sheet 4 1- ooo ooooopqooooooo Em |52 i I i INVIZN'IUR. BryantEdwards His AH'y;

Sept. 20, 1971 B. EDWARDS CONTINUOUS MOTION CONTAINER MOLDING MACHINEFiled July 28, 1969 11 Sheets-Sheet 5 INVEN'I'OR. Bryant Edwards BY WHis AH'ys Sept. 20, 1971 B. EDWARDS CONTINUOUS MOTION CONTAINER MOLDINGMACBINE riled July 28, 1969 ll Sheets-Shoat 6 INVEN'I'OR. Bryant EdwardsBY h His Alf'ys Sept. 20, 1971 B, E S 3,605,192

CONTINUOUS MOTION CONTAINER HOLDING MACBINE Filed July 28, 1969 7 l1Sheets-Sheet. 7

l I cu wg "i 3 x 1""AA A INVIiN'IOR. Bryant Edwards BY 4/ M His AH'ysB.'EDWARD$ CONTINUOUS MOTION CONTAINER MOLDING MACHINE Filed July 28,1969 Sept. 20, 1971 11 Sheets-Sheet 8 w zze INVEN'I'OR. Bryant EdwardsB. EDWARDS CONTINUOUS MOTION CONTAINER MOLDING MACHINE Filed July 28,1969 Sept. 20, 1971 11 Sheets-Sheet 9 DRUM ROTATION CAVITY 8 5 H mm M .5w. w M I M Sept. 20, 1971 B. EDWARDS CONTINUOUS MOTION CONTAINER MOLDINGMACHINE Filed July 28, 1969 11 Sheets-Sheet l0 INVEN'IOR. Br am faydsHis AH'ys Sept. 20, 1971 B. EDWARDS CONTINUOUS MOTION CONTAINER MOLDINGMACHINE Filed July 28, 1969 12. Sheets-Sheet U INVI'JN'IHIL Bryanl-Edwards BY d4} His Aff'ys United States Patent 01 lice US. Cl. 1819R 27Claims ABSTRACT OF THE DISCLOSURE A continuous motion container moldingmachine is provided with cooperating molds which operate upon heatedthermoplastic sheet or web material to form disposable containers. Theheated sheet material web is continuously delivered to the cooperatingmolds, the transfer therebetween being accomplished by circumferentialweb clamping means along a coincidental path when synchronized with thespeed of the moving web, thereby enabling the cooperating mold means toform thin-wall, substantially uniform-in-thickness, containers from thematerial clamped off from the remainder of the moving web. Uniquesubstations of the continuous motion container molding machine includingsheet delivery, web clamping, scrap removal, and cup ejectionsubstations are also disclosed.

Disposable, thin-wall plastic cups and containers for vending orover-the-counter use are being used in increasing numbers as consumersbecome aware of the many advantages such cups possess over paper cups,whether coated or impregnated with wax or plastic. Some of the morewell-known advantages include, among others, the characteristics ofbeing liquid tight, sanitary, taste free, moisture impervious, and vaporinhibiting. Consumers have appreciated these qualities in disposable orexpendable containers.

Several techniques have been employed in the fabrication of throw-awayor expendable plastic containers. During the early stages of plasticcontainer development, wellknown injection molding techniques wereadapted to the manufacture of such containers. Fabrication of plasticcontainers by this method included the injection of hot plastic materialunder pressure into a confined mold which conformed to the ultimatecontainer configuration. Injection molded containers necessarily possessrelatively thick walls which result in containers utilizing more plasticmaterial than was required in order to economical- 1y compete with theirpaper cup counterparts. This factor, coupled with the limiting speeds inproducing plastic containers, made this process relatively ineffectivefrom a competitive standpoint.

The inability to produce relatively thin-walled plastic containers inhigh-volume production by the injection molding process contributed, atleast in part, to the development of thermoforming techniques andprocesses where a heated sheet of thermoplastic material is molded toform container products. This method is best exemplified by the use ofpositive or negative fluid pressure, with or without mechanicalengagement of the heated plastic web to be formed into the desiredthin-walled container shape. The speed of this process, together withthe relatively thin-walled character of the plastic containers and themany diverse configurations that are possible with this method, hascontributed significally to the impetus of disposable or expendableplastic cups and containers.

As presently known, there are certain limitations in the thermoformingprocess since it is an intermittent sheet-advance and molding technique.Currently, it is the practice to intermittently feed heatedthermoplastic 3,605,192 Patented Sept. 20, 1971 sheet or web material toa molding station where reciprocating molds, positioned on oppositesides of the web, are advanced to form the container product. Heat is anecessary ingredient in the thermoforming process in order to fabricatethe desired container configuration, and it has been found that thecooling of the container after formation thereof, in order to eject orremove it from the mold, constitutes a relatively high percentage of thetime required to form containers as compared with the other steps in thethermoforming cycle. Additionally, forming cycle time is increased asthe result of the dead times involved in the intermittent feeding of theheated sheet to the molding station, the opening and closing of the webclamps and molds, and the ejection or removal of containers from themolds.

There have been some recent proposals which have combined injectionmolding and thermoforming techniques for the purposes of a fastermolding cycle with lower injection pressures than is possible withconventional injection molding methods. Such processes, which have beentermed injection blow molding, require the intermittent placement offormed plastic disks of predetermined thickness in intermittentlyreciprocal molds as in the typical thermoforming process, and therefore,do not avoid the large cooling times and dead-time aspects of the sheettransfer, clamp and mold movement, and cup ejection.

In the present invention a continuous motion container molding machineis disclosed which overcomes, in large measure, the above stateddisadvantages of the thermoforming process. Continuous motion plasticbottle machines have been proposed, principally for non-nesting,blow-molded products; but there has been no suggestion that thecontinuous manufacture of open-mouthed, plastic containers can beadapted to the thermoforming technique.

It is an object of the present invention to provide a continuous motioncontainer molding method and apparatus for the manufacture ofopen-mouthed, thin-walled containers.

Another object of the present invention is the provision of a method andapparatus of the aforementioned type which overcomes many of thedisadvantages inherent in the thermoforming process while retaining allof the advantages thereof.

A further object of the present invention is the provision of a methodand apparatus of the type described which incorporates a continuoussheet or web feeding system which rapidly delivers heated sheet or webmaterial to a container molding station at the proper time and location.

Still another object of the present invention is the provision of amethod and apparatus which includes a container molding stationproviding circumferential clamping of the heated sheet or web materialalong a coincidental path when synchronized with the speed of the sheetor web to provide a defined or predetermined material section which doesnot include fold lines of varying thickness as is essential for thefabrication of thin-walled plastic containers having uniform wallthickness without weakened or unnecessarily rigid sections.

A still further object of the present invention is the provision of acontainer molding method and apparatus as aforementioned which provideseffective scrap removal, as well as the ejection and removal of formedcontainers in an oriented fashion for subsequent delivery to a rimrolling station or the like.

The above and other objects and advantages of the present invention areattained by the provision of a continuous molding method or apparatuswhich includes the steps or means of feeding a heated thermoplastic webto at least one pair of continuously rotating cooperating molds,

simultaneously attaching the web to the molds for predeterminedcoincidental movement therewith and clamping off a predeterminedmaterial area from the remainder of the web, and forming containers fromthe predetermined material arca when attached to the cooperating molds.

Reference is now made to the accompanying drawings wherein:

FIG. 1 is a top plan view of the continuous motion container moldingmachine embodying the principles of this invention;

FIG. 2 is a side elevational view of the apparatus of this invention;

FIG. 3 is an enlarged fragmentary end elevational view depicting theendless container molding station of the invention;

FIG. 4 is an enlarged fragmentary sectional view of the containermolding station as viewed along a substantially vertical plane sectionthereof;

FIG. 5 is an enlarged fragmentary elevational view of the web feedingapparatus as it delivers a heated web of material to the containermolding station and is then subsequently disengaged from the web;

FIG. 6 is an enlarged end elevational view of one of the web conveyorclip means associated with the web conveying apparatus of the presentinvention;

FIG. 7 is an enlarged, partially elevational and sectional view furtherillustrating one of the web conveyor clip devices;

FIG. 8 is an enlarged fragmentary elevational view illustrating the webconveying apparatus in conjunction with the web clamping means of thecontainer molding station.

FIG. 9 is a further enlarged fragmentary view of the web clamping meansattached to the container molding station;

FIG. 10 is also an enlarged elevational and sectional view of the webclamping means mounted on the container molding station;

FIGS. llA-l 1E are fragmentary semi-diagrammatic representations of theprincipal steps in the forming of containers at the container moldingstation;

FIG. 12 is a timing diagram which shows the relative movement and times,as well as the respective position, of the web clamps and mold andplunger elements in the container molding operation;

FIG. 13 is a fragmentary side elevational view illustrating the openingof the cooperating molds at the end of the forming cycle and the removalof the formed containers from the container molding station; and

FIG. 14 is a fragmentary side elevational view of onehalf of thecontainer molding station as viewed transverse to the vertical planeextending therebetween and showing the scrap pick-01f wheel and cupremoval substations of the present invention.

GENERAL DESCRIPTION OF THE MACHINE As best seen in FIGS. 12 of thedrawings, the continuous motion container molding machine generallyidentified by the numeral 10 includes a reel storage station 12 where upto two reels 14 of thermoplastic sheet or web material 16 are mountedfor sequential use by the machine 10. A reel loading station 15, Wherethe reels 14 are kept prior to use thereof, forms part of the reelstorage station 12. The leading edge of the sheet or web material 16from any of the reels 14 is delivered to the web take-up and in-feedstation 18 Where a plurality of web feeding rollers 20 are provided fortransferring the web 16 at the desired predetermined speed which issynchronized with the other substations of the machine. Suitable dancerrolls or the like which provide web take-up and web register systems toprovide proper positionment of the trailing and leading edges of thewebs 16 from any two reels 14 are preferably employed to assure anuninterrupted transfer or delivery of webs 16 to the other substationsof the machine 10.

The main web feeding system comprises the endless web conveyor means 22which is arranged to deliver the web 16 of thermoplastic material fromthe web take-up and in-feed station 18 through a web heating station 24to the container molding station 40. The Web conveyor means 22 includesa plurality of spaced web conveyor clip devices 26 which are attached toa driven endless chain or belt 28 and arranged to grip the Web 16 beingfed through the machine 10 along the upper margin thereof. The webconveyor clip means 26 grip the upper margin of the vertically orientedweb 16 being fed through the machine adjacent the web take-up andin-feed station 18 for delivering the web 16 therefrom to the containermolding station 40. As previously noted, the web 16 is passed throughthe heating station 24 en route to the container molding station 40, andfor this purpose the lower run of the endless chain or belt conveyor 28carries the web 16 through a series of heater banks 30 positioned alongthe path of the moving web 16. Each of the heater banks 30, shown inFIG. 2 of the drawings to be four in number, contains vertical calrodunits or other suitable heating mechanisms (not shown) which arearranged on opposite sides of the moving web 16 to provide the properheating environment for the web 16 prior to its being delivered at thesuitable heated temperature to the container molding station The calrodor other heating element of each heater bank 30 is preferably mounted inthe lower movable section 32 which is mounted for pivotal movement at34. Air cylinder devices 36 or the like are connected to the lowermovable section 32 of the heater banks 30 and are arranged to beactuated by suitable electronic controls to laterally displace the lowermovable sections 32 containing the heating elements away from the movingweb 16 whenever the machine 10 is stopped. This prevents the heaterbanks 30 from melting the web 16 in the event that the machine 10 isstopped for one reason or another.

The web or sheet 16, after suitable heating thereof to the prescribedtemperature, is then delivered to the container molding station 40 wherean endless rotary drum 412 containing web clamping and mold members, aswill be discussed in detail below, operate on the web to formsubstantially uniform in thickness, thin-wall, nestable plasticcontainers from the heated thermoplastic web 16. As will be apparentfrom the description that is to follow, all of the web 16 is notutilized in the fabrication of the plastic containers; therefore, ascrap removal means 44 is provided for carrying away the web scrap to agranulator mechanism (not shown). The containers which are formed areremoved from the continuously rotating drum 42 by the pneumaticcontainer removing tube 46 which delivers the formed containers inoriented fashion to a rim rolling station (not shown) where the cups arerim rolled and then transferred to a cup removal station where theformed plastic containers are packed for shipment to the ultimateconsumer.

It is within the contemplation of the present invention that formedplastic disks can be delivered by suitable con veying mechanisms to thecontainer molding station where the continuous forming of plasticcontainers according to the injection blow-molding technique can beperformed. In the preferred form of the invention, a web ofthermoplastic material 16 is utilized, and in the discussion that is tofollow specific description will be given regarding this preferredembodiment of the invention.

CONTAINER MOLDING STATION In order to understand the functioning andoperation of the various substations of the machine 10, it will behelpful to first have in mind the structure and operation of thecontainer molding station 40. This station is best illustrated in FIGS.34 of the drawings. The container molding station 40 includes upright,generally opposed frame elements 48, 49 which are interconnected by upper and lower supporting beams 50. The motor 52 is mounted at one sideof the container molding station as seen in FIG. 1 and drives an endlessbelt 54 which is entrained about motor guide pulley 56 and framesupported guide pulley 58, the latter in turn driving the upper spurgear 60 which meshes in toothed engagement with the lower spur gear 62,as seen in FIG. 4 of the drawings, for driving or rotating the shaft 64upon which the rotary drum 42 is mounted. It will be appreciated thatthe guide pulley 58 and the upper spur gear 60 are suitably journaled ona frame supported shaft 63 while the lower spur gear 62 is fixedlymounted in an external fashion about the rotary drum shaft 64 at one endthereof as best seen in FIG. 4 of the drawings.

The rotary drum shaft 64 is illustrated in FIG. 4 as comprising athree-piece shaft having hollow, relatively smaller shaft sections 66,68 at opposite ends thereof which are supported by the frame elements ofthe machine. and a hollow, relatively larger intermediate shaft section70 which supports the web clamps and cooperating molds. The hollowthree-piece rotary drum shaft 64 is utilized for carrying cooling tubesor the like which are connected to the cooperating molds for cooling thecontainer product after forming thereof.

The relatively smaller, hollow shaft sections 66, 68 are supported atthe outermost ends thereof by tapered rollerbearing assemblies 72, 74respectively which are, in turn, supported by the upright, verticalframe elements 48, 49 respectively at opposite ends of the containermolding station 40. The innermost portions of each of the relativelysmaller, hollow shaft sections 66, 68 are mounted within complementaryconfigured openings at opposite ends of the relatively larger, hollowshaft section 70.

The intermediate rotary drum shaft section 70 fixedly mounts, atopposite ends thereof, cylindrical mandrel and mold cavity supportingplatens 76, 78 respectively. The mandrel and mold supporting platens 76,78 are provided with central openings 80, 82 respectively, which arecomplementary configured relative to the external configuration anddimension of the intermediate shaft section 70, and may be eitherfrictionally locked together or have means for restraining either rotaryof lateral movement of the mandrel and mold supporting platens 76, 78relative to the intermediate shaft section 70. Toward this latter end,it will be noted that the mandrel and mold supporting platens 76, 78respectively include, adjacent the central openings 80, 82 thereof,inwardly extending flanges 84, 86 respectively which aid in preventingmovement of the mandrel and mold supporting platens 76, 78 toward oneanother.

Each of the mandrel and mold supporting platens 76, 78 at the outermostperiphery thereof include axially aligned, spaced journal supports withassociated bushing elements. Specifically, the mandrel supporting platen76 includes axially spaced journal supporting sections 88, 90 into whichare mounted associated bushings 92, 94 respectively for reciprocallymounting the mandrel shaft 96. In the case of the mold supporting platen78, the axially spaced journal supports 98, 100 include associatedbushings 102, 104 which reciprocally mount the mold shafts 106.

The manner in which the mandrel and mold shafts 96, 106 respectivelycarry the cooperating mold elements and move with respect to one anotheris best seen by comparing the elevational and sectional views of therotary drum 42 illustrated in FIGS. 34 of the drawings. Consideringfirst the mandrel shaft 96, it will be noted that the innermost orforward end thereof includes a mandrel or plug 108, a mandrel block 110including cutting elements as will be described, and a mandrelsupporting block 112. At the rear or outermost end of the mandrel shaft96, there is provided a rear shaft guide block 114 and a cam follower116 on opposite sides thereof. In the case of the mold cavity shaft 106,the forward or innermost end thereof includes the mold cavity 118 havingassociated therewith cutting elements complementary to those carried bythe mandrel block 110, a container ejector or knock-out plug mechanism120 and a mold cavity supporting block 122. The rear or outermost end ofthe mold cavity shaft 106 has associated therewith at opposite sidesthereof a rear mold cavity shaft guide block 124 and a cam follower 126.

During the forward and rearward movement of the mandrel and mold cavityshafts 96, 106, the axially spaced journal supporting sections 88, inthe case of the mandrel shafts 96 and the axially spaced journalsupporting sections 98, associated with the mold cavity shafts 106assure essentially linear movement of the cooperating mandrels and moldcavities 108, 118 respectively and associated parts thereof. The rearmandrel and mold cavity shaft guide blocks 114, 124 respectively includecomplementary surfaces or interfitting portions on adjacents shaft guideblocks to prevent any rotary movement of the shafts 96, 106 during therotary movement of the rotary drum station 42. In this way, thecooperating mandrels and mold cavities 108, 118 respectively will movetoward and away from one another without any adverse influence fromcentrifugal forces during the rotation of the rotary drum station 42.

Reciprocating movement of the mandrel and mold cavity shafts 96, 106 isachieved by the movement of the cam followers 116, 126 in a cam slot ortrack. For this purpose, there is provided a mandrel barrel cam 128having a cam slot or track 130 in which the cam followers 116 of eachmandrel shaft 96 ride. A mold cavity barrel cam 132 is also provided andhas formed therein a cam slot or track 134 in which the cam followers126 of the mold cavity shafts 106 ride. The mold cavity barrel cam 132further includes a cam slot or track in which guide followers of the webclamp mechanism ride as will be presently described.

The mold cavity barrel cam 132 is fixedly mounted to the upright framesupport 49 at the right-hand side of the machine as viewed in FIG. 4 ofthe drawings. The mandrel barrel cam 128 is also fixedly mountedrelative to the rotary drum shaft 64, but permits limited lateralmovement of the cam, together with the mandrel shafts 96 in the event ofweb jam-up or other such occurrence. In this regard, it will be notedthat the mandrel barrel cam 128 is non-rotatively supported relative tothe frame element 48 at the left-hand side of the rotary drum station 42in FIG. 4 of the drawings by a plurality of fixed shafts 138 which arejournaled in the frame element 48. Each of the shafts 138 includesspaced bearing-bushing assemblies 142, 144 respectively supporting therotary fixed shafts 138 for limited lateral movement between theenlarged head 148 at the free end of the shafts 138 and the innermostface or surface of the upstanding frame support 48. An annular supportmember 148 couples the shafts 138 and bearing-bushing assemblies 142,144 to one another to provide circumferential support for the mandrelbarrel cam 128. In order to provide the limited lateral movement of themandrel barrel cam 128 along the shafts 138, means (not shown)preferably coupled to the circuit of the machine is provided tolaterally displace the mandrel barrel cam 128 in the event of web jam-upor other similar occurrence.

In order to achieve the fabrication of substantiallyuniform-in-thickness, thin-wall plastic containers with no weakened orunnecessarily thickened portions, it is necessary that a predeterminedmaterial section of the web 16 to be clamped on opposite sides thereofprior to engagement by the cooperating molds. The specific manner inwhich the clamps operate in a continuous motion machine will bedescribed in detail below, but it is important to understand theenvironmental setting in which the clamps are mounted on the rotary drumstation 42. This can be best understood by again referring to FIG. 4 ofthe drawings which shows generally opposed pairs of circumferential webclamping means 150, 152 intermediate the mandrel and mold cavity 108,118 respectively. The circumferential web clamping means 150, 152 aredesigned to clamp a predetermined material section of the web 16 in acircumferential manner about the peripheries of the mandrel and moldcavity 108, 118 respectively to permit these cooperating molds tooperate upon the predetermined material section in a manner to bedescribed.

The web clamp is supported by the web supporting block 154 which, inturn, is supported by the upstanding external flange 156 integrallyconnected to the intermediate shaft section 70 of the rotary drum shaft64. In order to permit rotary and angular adjustment of the web clamps150, 152 as will be described below, a cam follower 158 which rides inthe cam slot 160 of the face cam 162 is connected to a bell-crankmechanism 164, partially shown in FIG. 4 of the drawings which will bemore specifically described in connection with FIGS. 8l() of thedrawings. Controlled angular and rotary movement of the web clamp 152,along with the web clamp 150, is achieved by the common shaft 166 at oneend of the bellcrank mechanism 164.

Web clamp 152 is vertically supported by the intermediate shaft section70 by way of the web supporting block 168 and the web guide roller 170which rides in a guide slot 258 in ring guide slot member 260 which isgenerally parallel with the axis of the rotary drum shaft 64.

Each web clamp 152 is reciprocated relative to the web clamp 150 by wayof the shaft 172 which is connected at one end to the web supportingblock 168 and at the other end is provided with a cam follower 174 whichis guided in the cam slot or track 136 formed in the mold cavity barrelcam 132. The shaft 172 is journaled adjacent the cam follower end in abushing 176 and adjacent the other end is supported in a bushing-bearingassembly 178, in turn, supported by an externally projecting integralflange 180 of the intermediate shaft section 70. Each mold clamp 152 isnormally biased in a clamped position relative to the mold clamp 150 asthe result of the helical coil spring 182 which is maintained in acompressed state by the spring clamping plates 184, 186, thereby urgingthe shaft 172 and its associated web clamp 152 into clamped arrangementwith its respective web clamp 150. As the cam follower 174 follows thecam slot 136, the helical coil spring is further compressed, therebyopening up the web clamps 150, 152 as can perhaps be best seen whenconsidering FIGS. 34 of the drawings in conjunction with one another.

With the understanding of the structure and operation of the containermolding station in mind, it will be easier to understand the cooperationof the various substations 0f the machine 10 beginning with the webdelivery and concluding with the scrap removal and cup ejection.

WEB FEEDING SYSTEM In FIGS. 2 and 57, a web feeding system comprising anendless web conveyor means 22 is shown. The endless web conveyor means22 operates between the web take-up and in-feed station 18 through theweb heating station 24 to the container molding station 40. In generalthe web conveyor means 22 includes a plurality of spaced, web conveyorclip devices 26 which are attached to a driven, endless chain 28. Eachof the web conveyor clips 26 are designed to engage the web 16, as bestseen in FIGS. 5 and 8 of the drawings, along limited upper marginalareas of the vertically oriented web 16 in a manner so as not tointerfere with the circumferential web clamping means 150,152 of theendless rotary drum 42.

Each of the web conveyor clip means 26 is provided with a pair of freerotating rollers 188, which are mounted on opposite sides of the endlesschain 28. Each pair of rollers 188, 190 are mounted in a closed, endlesstrack (not shown) to prevent sagging of the endless chain belt 28. Theopposed pairs of rollers 188, 190 are mounted in the plane of theendless chain belt 28 and are supported on bushings 192, 194 which aremounted at opposite ends of the shafts 196. Fastening means in the formof a C-retaining ring 198 or the like prevents lateral movement 8 anddisassembly of the rollers 188, 190 relative to the shafts 106. As bestseen in FIG. 7 of the drawings, the shafts 106 extend through theendless chain 28, and thus are carried thereby along with the associatedpairs of rollers 188, 190.

For clamping the web 16 along the upper margin thereof. a pair of springbiased clamping elements 200, 202 are provided. The clamping elements200, 202 are configured and mounted relative to the endless chain 28 toprovide upper sections 204, 206 respectively which are generallyparallel to each other, middle body sections 208, 210 respectively whichgenerally have a sear-spring shape, and a pair of lower sections 212,214 which function to clamp the web 16 as will be presently described.The upper body sections 204, 206 of the clamping elements 200, 202respectively have suitably aligned upper and lower openings forreceiving the pairs of shafts 196 and the single lower shaft 216. Twopairs of retaining plates 218, 220 are mounted on the pair of shafts 196and shaft 216 on opposite sides of the upper sections 204, 206respectively of the clamping elements 200, 202. Nuts 222 threadablyassociated with the shaft 216 engage the outer plate of each of thepairs of retaining plates 218, 220 and clamp the upper sections 20 4,206 against the inner plates of the pairs of retaining plates 218, 220,the inner plate in each pair of retaining plates 218, 220, in turn,being supported by the endless chain 28 alorig outer faces thereof asindicated in FIGS. 67 of the drawings. This provides a stable and securemounting for each clamping element 200, 202 relative to the endlesschain 28.

The clamping elements 200, 202, when mounted to the endless chain 28 inthe manner just described, enable the sear-spring spaced middle bodysections 208, 210 respectively to maintain the lower clamping sections212, 214 in a closed osition as best illustrated in FIG. 7 of thedrawings. Thus, the clamping elements 200, 202 are normally springbiased to a closed position to assure gripping of the web 16 for theunimpeded delivery thereof to the various substations of the machine 10.

In order to open the lower clamping sections 212, 214 of the clampingplates 200, 202 respectively to permit the engagement and disengagementwith respect to a web 16, there is provided a plunger element 215associated with each web conveyor clip means 26. Each plunger element215 includes a head portion 217 and an elongated shank 219 having avertical slot 221 therein for mounting the plunger 215 relative to theshaft 216 while permitting limited vertical movement thereof, and anenlarged foot section 223 with integral wing elements 225, 227 which aremounted in longitudinal openings 228, 230 of the searspring shapedmiddle body sections 208, 210. The limited vertical movement of eachplunger 215, permitted by the vertical slot 221, is complemented by thespherical shape on the lower face of the enlarged foot section 223which, when the plunger 215 is depressed, moves the downwardly andinwardly tapering portions of the middle body sections 208, 210 apartfrom one another to open up the clamping sections 212, 214 as isillustrated in FIG. 6 of the drawings. The wing elements 225, 227 movewithin the longitudinal openings 228, 230 when this occurs, therebyassuring stability to the plunger element 215 during its movement.Upward movement of a plunger element 215 will then cause the sear-springshaped middle body section 208, 210 to move the clamping sections 212,214 respectively to their normally clamped or closed position.

' The plunger elements 215 are depressed adjacent the Web take-up andin-feed station 18 in order to permit the web conveyor clips 26 to gripthe web 16 adjacent the upper margin thereof and also after the web 16has been clamped to the rotary drum 42 by the opposed circumferentialweb clamping means 150, 152. While any suitable means may be employedfor this purpose, it has been found that a sprocket wheel 232 with aspecially configured tooth formation 23-1 is very effective in engagingthe heads 217 of the plunger elements 215 and depressing them at thedesired moment.

9 WEB CLAMPING MECHANISM The web conveyor clips 26 are disengaged fromthe Web 16 in sequential fashion as the circumferential web clampingmeans 150, 152 are sequentially attached to the web 16. The transfer ofthe web 16 from the web conveyor clips 26 to the circumferential webclamping means 150, 152 is an important part of the continuous motionmolding operation for a number of reasons. The web 16 follows avertically oriented, linear path while being fed by the web conveyorclip means 26, and after clamping by the circumferential web clampingmeans 150, 152 is then caused to move in a predetermined arcuate pathabout the rotary drum 42. This necessitates the clamping of the web bythe circumferential web clamping means 150, 152 along a coincidentalpath when synchronized with the speed of the web in order to assurepredetermined, simultaneous movement of the web 16 and Web clampingmeans 150, 152 along a predetermined path. Failing to clamp the web 16in the manner just described as it is converted from linear to arcuatemovement will cause undesirable stretching and fold lines in the webwhich will result in unnecessarily thin or thickened sections in theultimately formed container. These difficulties can be avoided byclamping off a predetermined material area of the web 16 by thecircumferential web clamping means 150, 152 before the web 16 begins itsarcuate movement, thereby segregating selected web areas which can beoperated upon by the cooperating mold to form containers. Any stretchingor material folding outside of the circumferentially clamped areas doesnot interfere with the molding operation or create undesired thinned orthickened sections in the container that is formed.

The structural components of the web clamping means and its operationcan best be understood by reference to FIGS. 8-10 of the drawings. InFIG. 8 of the drawings the movement of the adjacent pairs of web clamps150, 152 through a circumferential path, including both arcuate andlinear movement of the web clamps 150, 152 during rotation thereof isillustrated. The web clamps 150', 152 are mounted on the rotary drum 42as illustrated in FIG. 4 of the drawings, such that the web clamps willbe rotated in the general vicinity of the moving web 16. When the webclamps 150, 152 are synchronized with the speed of the moving web 16,means are employed to assure coincidental movement of the web clamps150, 152 along a linear path coinciding with the moving web in order topermit clamping of the web 16 by the web clamps 150, 152 when they aretraveling in the same path at the same speed. In general, the meansemployed to assure coincidental, synchronized movement of the web clamps150, 152 and the moving web 16 comprises a cam follower 158 for each webclamp means 150*, 152 which rides in a cam slot 160 of the face cam 162which is fixedly mounted relative to the base of the machine by a clampconnected between the face cam 162 and the supporting beam 50 as can beseen in FIG. 4 of the drawings. The face cam 162 is rotatively supportedon the intermediate shaft section 70 as can be seen in FIG. 10. Each camfollower 158 is attached to a bell-crank mechanism 164, to be presentlydescribed, which provides rotational and angular adjustment of each pairof web clamps 150, 152 in order that it may assume a coincidental pathsynchronized with the speed of the web 16 prior to clamping thereof. Theshape of the cam slot 160, together with the relative position of thecam follower 158 and its associated bell-crank mechanism 164 for pairsof web clamps 150, 152 at different relative circumferential positionsabout the rotary drum 42, can be best seen in FIG. 8 of the drawings.

Referring now to FIG. 10 of the drawings, it will be seen that each webclamping mechanism comprises a pair of generally opposed,circumferential web clamping elements 150, 152 which cooperate togetherto clamp off a predetermined material area of the web 16 as discussedabove. Web clamp 150 includes a clamp ring holder 234 10 which supportsthe movable clamping ring 236, the latter, in turn, having a retainingring 238 which is attached thereto by the fastening means 240 to preventany horizontal movement of the clamp ring 236. Similarly, the web clamp152 includes a clamp ring holder 242 which supports the clamping ring244 with the clamping ring 244 being attached to the retaining ring 246by the fastening means 248 to restrict horizontal movement of the clampring 244 relative to the clamp ring holder 242.

Clamp ring holder 234 is attached, by the fastening means 250, to theweb clamp supporting block 154 which, in turn, is supported by theexternal fiange 156 of the intermediate shaft section 70 forming part ofthe rotary drum shaft 64. The web clamp supporting block 154 includes atransverse opening for receiving part of the bellcrank mechanism 164 aswill presently be described.

The clamp ring holder 242 of clamp ring 152 is attached, by way of thefastening means 254, to the web clamp supporting block 168 whichincludes a depending leg 256 attached to a guide roller 170 riding in aguide slot 258 which is generally parallel with the axis of the rotarydrum shaft 64 as can be understood by comparing FIGS. 9l0 of thedrawings. Each guide slot 258 is formed in a ring guide slot member 260attached to the intermediate shaft section portion 70 of the rotary drumshaft 64. The web clamp supporting block 168 is also provided with atransverse opening as is the case with the web supporting block 154supporting the clamp ring 150, but in the case of the web clampsupporting block 168, the transverse aperture or opening 262 thereofreceives a shaft 172 which is retained therein by suitable means. Aspointed out in connection with FIG. 4 of the drawings, shaft 172 isconnected to a cam follower 174' which is guided in the cam slot ortrack 136 provided in the mold cavity barrel cam 132 and controls thereciprocating movement of the mold clamp 152 from a normally closedposition in clamping engagement with the web 16 to a position where theweb clamps 150, 152 are separated from one another.

The bell-crank mechanism 164 includes a first arm 262 which is attachedto the cam follower 158, a second arm 264 laterally spaced therefrom andoffset at a angle relative to the first arm 262, a connecting shaft 266which connects the first and second arms 262, 264 of the bell crank, anda shaft 166 common to both of the web clamps 150, 152 and journaled inbushings 268, 270 of the web clamps 150, 152 respectively adjacent thelower ends thereof. Connecting shaft 266 extends through the opening 252in the web supporting block 154 and is mounted within the bushing 272for limited rotational movement thereof. Shaft 166, common to both webclamps 150, 152, provides relative sliding movement therealong as wellas providing limited rotational movement of the clamp rings 236, 244along the lower end thereof.

It will be apparent, when comparing FIGS. 8 and 10, that each camfollower 158 as it moves along the cam slot or track moves the firstbell-crank arm 262 in different angular positions, and since the secondbell-crank arm 264 is connected thereto by the shaft 266 at a 90 offsetposi tion relative to the first crank arm 262, the second bellcrank arm264 will be moved in different angular positions 90 out of phase withthe different angular positions of the first bell-crank arm 262. Thevarious angular positions of the second bell-crank arm 264 will betransmitted through the common shaft 166, thereby causing both verticaland angular movement of the web clamps 150, 152 as each cam follower 158thereof is moved in the cam slot 160.

The web clamp mechanism for each pair of web clamps 150, 152, inaddition to providing angular and rotational movement thereof relativeto the moving web 16 in order to assume a coincidental path synchronizedwith the speed of the web prior to the clamping thereof, also providescircular movement of the web clamps 150, 152 in a predetermined arcuatepath during the container forming 1 1 operation. The web clampingmechanism also is designed for low inertia and Wear to enable operationthereof at high speeds.

GENERAL OPERATION OF THE MACHINE Reference to FIGS. llA-llE whichillustrate the principal steps of the container molding operation,together with the timing diagram of FIG. l2 depicting the relativepositions of the web clamps, mandrel and mold cavity throughout a 360machine cycle, will provide an insight into the general operation of themachine. FIG. 12 of the drawings also provides a cross reference toFIGS. 1lA 11E by indicating the approximate portion of the mold cyclewhere the various FIGS. llA-llE representations take place.

With the rotary drum 42 rotating as indicated in FIG. 12 of thedrawings, the first step in the container molding operation isillustrated by FIG. 11A where the web clamps 150, 152 are depictedseparated from one another. From the illustrated position, the webclamps 150, 152 will begin to close as an incident to the ultimateclamping of the web 16 at a later portion of the machine cycle. Thecooperating mandrel 108 and mold cavity 118 are at their maximumseparated distance from one another as a concluding phase to theprevious container molding operation so as to permit ejection andremoval of the thin-wall, plastic container C, which is drawn by vacuuminto the pneumatic tube 274 as will be described more in detail below.Ejection of the container C from the female mold cavity 118 isaccomplished by the ejector or knock-out plug mechanism 120 whichincludes an enlarged head section 276 received within a recess in thebottom of the mold cavity 118. The enlarged head 276 of the knock-outplug mechanism 120 further includes a depending, elongated shank 278having generally opposed, integral lug elements 280, 282 Which aredisposed in a slot formed in the shaft 106. Helical coil spring 284normally biases the knock-out plug mechanism toward the mold cavity 118such that it forms the bottom wall of the mold cavity during the moldingof a container, and upon the relative separation of the mandrel and moldcavity 108, 118, respectively as illustrated in FIG. 11A of thedrawings, the integral lug elements 280, 282 engage the journal support98 of the mold cavity supporting platen 78, thereby providing upwardmovement of the knock-out plug mechanism causing ejection of thecontainer C as illustrated in FIG. 11A of the drawings.

The beginning of one molding cycle and the conclusion of the previousone is somewhat intertwined in that the web clamps 150, 152 begin toclose at approximately 300 of a mold cycle where both the mandrel andmold cavity 108, 118 respectively continue to retract in order to permitejection and removal of the container C from the mold cavity 118 asdepicted in FIG. 11A. This merging of the beginning and concludingphases of sequential mold cycles produces an overall shorter mold cycletime.

As the web clamps 150, 152 are closing, the heated web 16 ofthermoplastic material is being carried to the rotary drum 42 by the Webconveyor clips 26. As has been previously discussed in connection withFIGS. 8-10 of the drawings, the web clamps 150, 152 are being angularlyand rotationally adjusted as they approach the moving web 16 in order toassume a coincidental path synchronized With the speed of the web priorto the clamping thereof. The clamping of the web 16 occurs atapproximately 9 before top dead center in the timing diagram of FIG. 12,and this position is represented by FIG. 11B in the drawings. The webconveyor clip 26 is released or disengaged from the moving Web 16 afterthe web clamps 150, 152 engage and clamp off a predetermined materialarea of the web. When clamped by the web clamps 150, 152, the moving web16 is attached to the rotary drum 42 thereby causing the web 16 to movein a predetermined arcuate path as perhaps can best be seen in FIG. 8 ofthe drawings. As the web 16 is clamped by the web c amps 150,

152, the mandrel and mold cavity 108, 118 respectively are being movedrelatively toward each other by their respective barrel cam/cam followerarrangements previously described.

The next stage of the molding cycle is represented by FIG. 11C of thedrawings wherein the predetermined clamped-off material area of the web16 is being mechanically engaged by the mandrel 108 as the mandrel 108and mold cavity 118 are moved relatively toward one another. Themechanical assist phase of the molding cycle as is represented in FIG.11C of the drawings is taken at approximately 50 of the mold cycle shownin the time diagram of FIG. 12. It is, of course, Well known in the artthat the mechanical assist pre-drawing of a heated thermoplastic webgreatly facilitates distribution of the material in the ultimatelyformed container. It will be noted that the mandrel 108 and mold cavity118 have not been closed relative to one another during this pre-drawingphase of the molding cycle.

FIG. llD of the drawings shows the molds after expansion of thecontainer by air pressure and also after the container has been severedfrom the web. When the mandrel 108 and mold cavity 118 are first movedto a closed position, cooperating annular shoulders 286, 288 formed inthe mandrel block 110 and mold cavity 118 respectively are brought intoengagement to seal 011 the predetermined drawn material area of the webwhich has been engaged by the mandrel 108. When the predetermined drawnmaterial area is so sealed olf from the remainder of the web, air underpressure is introduced substantially uniformly into the partially formedcontainer so as to expand and press the container wall against the innerwall periphery of the mold cavity 118. The air under pressure can beintroduced, for example, through the ports 290 of the mandrel 108 which,of course, is connected with a suitable source of air pressure (notshown). A vacuum or negative air pressure can be established through themold cavity 118, if this is desired; but in either case, differentialair pressure is established across the predetermined drawn areas orpartially formed container to expand the same against the inner Wallperiphery of the female mold cavity 118.

Following the expansion of the predetermined drawn areas or partiallyformed container, the mandrel 108 and mold cavity 118 are advancedtoward each other a slight amount so as to bring complementary cuttingor shearing edges associated with the annular shoulders 286, 288 intocooperative engagement for cutting or shearing the container thus formedfrom the unformed remaining web material. This is the position of thecooperating molds in FIG. 11D of the drawings which occurs atapproximately 225 of the mold cycle as can be seen in the timing diagramof FIG. 12. This cut-off in the mold technique is further explained indetail in US. Pat. No. 2,891,280, and thus further specific discussionthereof is unnecessary insofar as the present invention is concerned.

Following the cutting or severing operation, the mandrel and mold cavity108, 118 respectively begin to relatively separate from one another, anda short time thereafter, the web clamps 150, 152 then open to disengagethe remaining web portions or scrap web material therefrom. This isdepicted in FIG. 11E of the drawings, which is shown at approximately270 of the mold cycle. Once the remaining web portions or scrap webmaterial is released from the mold clamps 150, 152, it can then becarried away by the scrap pick-01f Wheel 44, to be presently discussedwhich carries the scrap web material away from the rotary drum 42 to agranulator mechanism (not shown). As the mandrel and mold cavity 108,118 respectively continue their relative separating movement, theknock-out mechanism will eject and remove the container C to permit thecarrying away thereof by the neumatic tube 274, also to be presentlydescribed.

1 3 SCRAP PICK-OFF MECHANISM 292 which is mounted for rotation aboutshaft 294 in a x direction opposite to the rotary drum 42. The rotatingpick-off wheel 292 includes fixed and moving gripper plates 296, 298,each having a plurality of aligned gripping fingers or teeth 300, 302respectively. The moving gripper plate 298 is laterally movable alongthe shaft 294 by a cam/ cam follower arrangement (not shown) which movesthe gripping fingers 302 into gripping engagement with the grippingfingers 300 of the laterally fixed gripper plate 296 at approximately285 from the top, dead-center position of the rotary drum 42. The scrapS is gripped by the rotating pairs of gripping fingers 300, 302 to carrythe scrap S away from the rotary drum 42. A curvilinear stripper plate304 is fixedly mounted relative to the moving pick-off wheel 292 inorder to strip the scrap S from the rotating pairs of cooperatinggripper fingers 300, 302 at a point where gravity is useful in carryingthe scrap S to a granulator or the like. The scrap pick-off wheel 44 issynchronized with the rotating drum 42 so as to remove the scrap Swithout in any way interfering with the molding of containers on therotary drum 42.

CUP REMOVAL MEANS As generally shown in FIG. 2 of the drawings, apneumatic container removing means 46 is included in the containermolding station 40 and extends upwardly and outwardly away from therotary drum 42 at a position which is approximately 300 from the top,dead-center position of the rotary drum 42. This is more clearlydepicted in FIGS. 13-14 of the drawings wherein the pneumatic containerremoving means 46 comprises a hollow cup ejector tube 274 which ispositioned adjacent mold cavities 118 beginning at approximately 310.The cup ejector tube 274 includes a lower curved section 306 whichgenerally follows the circular mold cavity placement for at least twomold cavities 118. On the side of the tube 274 which is adjacent themold cavities 118, the curvilinear section 306 of the cup ejector tube274 is provided with an opening 308 which intersects the curvilinearlower section 306 of the cup ejector tube 274 at an angle relative tothe axis thereof, as best illustrated in FIG. 13, to enable the cupejector tube to be mounted as close as possible to the mold cavities118. This arrangement permits containers to be rapidly deposited, whenejected from the mold cavities 118, into the opening 308 of the cupejector tube 274 so that the container C can be removed from the rotarydrum 42 without any interruption of the continuous molding operation. Avacuum is established in the cup ejector tube 274 by means connected toa suitable air source (not shown) which assists in the lifting and thepropelling of the container C to a collecting station which may includerim-rolling or forming means if desired.

From the foregoing it will now be appreciated that the continuous motioncontainer molding machine is capable of extremely high-speed manufactureof well-formed, thinwall plastic containers by utilizing variousstructural components and operating procedures not heretoforecontemplated.

I claim:

1. A continuous motion container molding machine comprising an endlesscontainer molding station mounted for continuous rotary movement aboutits axis, means for feeding a heated web of thermoplastic materialsubstantially tangentially to said endless container molding station andin a plane normal to the axis of the rotary molding station,circumferential web clamping means carried on said molding station forrotation therewith, means for moving said circumferential web clampingmeans relative to the rotational movement of said station and tocoincide with the tangential path of said web relative to said station,and at least one pair of cooperating molds attached to said endlesscontainer molding station and being operable upon said thermoplastic webwithin said circumferential we-b clamping means in a directionsubstantially parallel to the axis of said endless container moldingstation when said web is clamped to said endless container moldingstation.

2. The machine as defined in claim 1 wherein said endless containermolding station comprises a rotary drum.

3. The machine as defined in claim 1 wherein the axis of said endlesscontainer molding station is substantially parallel to the supportingsurface upon which said machine rests.

4. The machine as defined in claim 1 wherein the axis of said endlesscontainer molding station is substantially normal to the supportingsurface upon which said machine rests.

5. The machine as defined in claim 1 including a plurality of pairs ofadjacently positioned molds circumferentially arranged about saidendless container molding station.

6. The machine as defined in claim 1 wherein the web is moved in apredetermined arcuate path When clamped to said endless containermolding station.

7. The machine as defined in claim 1 wherein the plane of the web whenfed to said endless container molding station is substantially normal tothe axis thereof.

8. The machine as defined in claim 1 wherein said means for feeding saidweb becomes inoperative after said web is clamped to said endlesscontainer molding station.

9. The machine as defined in claim 1 wherein said means for feeding saidheated thermoplastic web includes web conveyor clip means for engagingsaid web in a limited area along the upper margin thereof.

10. The machine as defined in claim 9 wherein said Web conveyor clipmeans is disengaged from said web after said web is clamped to saidrotary container molding station.

11. The machine as defined in claim 9 including a plurality ofadjacently positioned clip means and web clamping means, the conveyorclip means being sequentially disengaged from said web upon thesequential clamping of said web by individual web clamping means.

12. The machine as defined in claim 1 wherein said clamping means moveson a linear path coinciding with the tangential path of said web for anincrement of movement prior to the clamping thereof.

13. The machine as defined in claim 9 wherein said clamping meansfollows a predetermined arcuate path on said forming station whenclamped to said web.

14. The machine as defined in claim 1 including independent clampingmeans associated with each pair of cooperating molds.

15. The machine as defined in claim 1 including a plurality ofadjacently positioned clamping means and cooperating moldscircumferentially arranged about said endless container molding station.

16. The machine as defined in claim 1 wherein each circumferential webclamping means comprises a pair of opposed clamping elements positionedon opposite sides of said web and said cooperating molds includes a moldcavity and mandrel element also located on opposite sides of said web.

17. The machine as defined in claim 1 and including means for severingcontainers from said web after formation thereof by said cooperatingmolds.

18.. The machine as defined in claim 17 wherein said means for severingsaid container from said web is associated with each pair of cooperatingmolds.

19. The machine as defined in claim 17 including means for removingcontainers from said endless container molding station.

20. The machine as defined in claim 19 wherein said means for removingcontainers comprises a pneumatic tube mounted adjacent to said endlesscontainer molding station.

21. The machine as defined in claim 19 and including means for grippingand carrying away the web scrap prior to the removal of said containers.

22. The machine as defined in claim 21 wherein said means for grippingand carrying away scrap web comprises a scrap pick-off wheel which ismounted for rotary movement opposite to the movement of said endlesscontainer molding station.

23. The machine as defined in claim 1 and including means for actuatingsaid cooperating molds and clamping means, said last mentioned meansproviding lateral separating movement of the cooperating mold means andthe clamping means in the event of web jam-up in the machine.

24. The machine as defined in claim 1 and including heating means forheating the web prior to molding thereof, said heating means beinglaterally displaceable from the web in the event of material jam-up inthe machine.

25. A continuous motion container molding machine comprising a rotarycontainer molding station including at least one pair of cooperatingmolds mounted for movement in a direction substantially parallel to theaxis of said rotary container molding station, means for feeding aheated thermoplastic web in a substantially linear path to said rotarycontainer molding station with the plane of said web being substantiallynormal to the axis of said rotary container molding station, clampingmeans for clamping said heated thermoplastic web to said rotarycontainer molding station, said clamping means being formed to move onsaid linear path of said web during clamping of said web and thereafterto move in a predetermined arcuate path with said rotary containermolding station, said clamping means being arranged to clamp off apredetermined material section from the remainder of the web foroperation thereupon by the cooperating molds which are associatedtherewith, said cooperating molds including a complementary mold cavityand mandrel element disposed on opposite sides of the predeterminedmaterial section, means for relatively moving the mandrel element andthe mold cavity toward each other to draw the predetermined heatedsection within the clamped area and provide a partially formedcontainer, means for sealing off the pre-formed container from theremainder of the thermoplastic Web, means for establishing a pressuredifferential within the partially formed container to expand it againstthe mold cavity to form the ultimate container configuration, and meansfor thereafter severing the container so formed from the remainder ofthe plastic sheet.

26. The machine as defined in claim 1, and means for adjusting the speedof feeding of said web to said molding station to be synchronized to thespeed of said web clamping means moving on said tangential path.

27. The method of molding articles from a web of material fedtangentially to a rotating article molding machine having a plurality ofcircumferentially disposed article molding elements comprising, clampingsaid web on a perimeter at a position prior to the tangentialintersection of said web with the periphery of said molding machine,carrying said web and said perimeter substantially linearly along thetangent line past said tangential intersection and contemporaneouslyproducing sufiicient clamping pressure to prevent any disturbance of theweb material within said perimeter responsive to further movement ofsaid web away from said tangent line, carrying said clamped perimeterand said web circumferentially of said machine for operation of saidarticle molding elements within said perimeter, and repeating saidforegoing steps.

References Cited UNITED STATES PATENTS 2,027,915 1/1936 Kux 182OR2,745,135 5/1956 Gora 264268X 3,069,725 12/1962 Root 18-5-RX 3,105,27010/1963 Fibish 18-19R 3,166,790 1/1965 Keyes 18-19R 3,218,379 11/1965Edwards 264292X 3,418,691 12/1968 Hanoi 1820RR ROBERT L. SPICER, JR.,Primary Examiner US. Cl. X.R.

